Coding or branding machines for applying an imprint at a predetermined location upon a package or other article traveling along a conveyor are well known in the art. Such machines must provide reliable operation at high speeds in order to keep up with state-of-the-art packaging machines that are capable of delivering as many as 250 cartons, cans or other articles per minute. Additionally, these machines must provide these high operational speeds without damaging the packages, as such damage can lead to machine jamming and spillage of the contents of the packages over the machine. With either of these occurances costly machine service is required and the resultant down time reduces overall productivity.
In an attempt to meet the above demands, U.S. Pat. No. 3,659,521 to Lany discloses an apparatus for marking articles on a moving conveyor. This prior art apparatus includes optical detectors for detecting an article and a pivotally mounted marker that is moved into an operative marking position upon the detection of an article. As should be appreciated, however, this apparatus is inefficient as valuable packaging time is essentially wasted during the period when the marker is moved into the operative marking position following article detection. Further, since the marker is not normally held in the operative position, the marker does not register with the articles in exactly the same relation each time, thereby tending to cause blurred or otherwise unsatisfactory imprinting.
In an effort to overcome these shortcomings, U.S. Pat. No. 4,047,479 to McKay et al discloses an article coding machine wherein the coding assembly or marker is normally held in operative engagement with the articles. This increases machine efficiency and speed of operation while improving imprint quality by insuring a proper, consistent register with the articles. The machine is also provided with a cylinder and cooperating piston for pivoting the coding assembly from the operative position away from the articles being imprinted so as to allow improved access for maintenance.
The McKay machine, however, is not without its disadvantages. It is not provided with any means for detecting, for example, a defective carton upstream of the coding assembly along the conveyor. Therefore, a defective carton can enter and wedge in the branding assemby thereby jamming the machine and requiring costly down time and manual labor to release and/or repair.
Thus, a need is identified for an anti-jam system capable of detecting a defective package or other article and displacing the coding assembly from the package path so as to allow the defective package to pass and prevent a shut-down of the machine. The system then returns the coding assembly to the operative position in proper registration along the conveyor path for properly imprinting the following packages.